Core aeration and over-seeding are great ways to improve the health of your lawn and to help it look its golf-course best. In this post, we'll be going over some methods of core aeration and over-seeding, best practices, and how you can tell if your lawn could benefit from these services.
Let's start with core aeration. This is a process where a core is removed from the lawn, making a small cylindrical hole and bringing of soil plug to the surface and depositing it on the surface of your lawn. The hole allows oxygen to reach the roots of your turf, keeping it healthy and green. The plug of soil breaks down redepositing nutrients and microorganisms on the surface of your lawn, while also giving the grass seed somewhere to germinate (more on this in the next section).
Core aeration can also provide better drainage, so it's a great solution for lawns that tend to get soggy or spongy after heavy rains. It can reduce compaction in the soil under the lawn and can even help limit how much thatch forms on your lawn by helping it to break down.
Over-seeding is, at its most basic, casting seed onto the surface of your lawn. Adding seed to an existing lawn can help it look fuller and also create competition for opportunistic weeds like dandelions, crabgrass and plantains. In fact, I find that simply improving the health and fullness of your turf is the single most effective method of controlling weeds.
In order for over-seeding to be effective the seed will need somewhere to germinate, plenty of water and something to cover it up (usually straw or straw mats are used, available at any home improvement store) while still letting in light to reduce the amount being pillaged by birds and blown around by the wind, as this can create areas with no seed coverage.
Germination of the grass seed is where core aeration comes into play. Remember those plugs of soil I told you about earlier? Those plugs and the holes they come from are excellent places for grass seed to take hold. Once the seed has been broadcast over the lawn, taking care to concentrate on areas that are bare or thinner, it is immediately watered and then covered with straw or straw mats to help lock in moisture and prevent it from being blown by wind or animals. The seed needs to be kept moist until it germinates which can take from 5- 30 days, or even longer in cooler temperatures, so at this stage watering is essential.
The best times to aerate and over-seed your lawn are Spring and Fall. Most sources recommend aerating every 1-3 years, but if your property is hilly, receives a lot of traffic (I'm talking to you, parents!), or has generally poor soil quality aerating up to twice a year can show noticeable benefits.